1. Field of the Invention
The present invention relates to the field of spring characteristics in vehicle suspension systems such as those used in bicycle and motorcycle suspension systems that are designed to improve compressibility of a spring system in response to riding conditions and the rider's weight.
2. Description of the Prior Art
Spring and shock distribution systems for changing the spring characteristics of a mountain bicycle fork depending on the riding conditions or the rider's weight are generally known. In the prior art, one way to change the spring characteristics is to change the entire spring assembly to a different spring assembly. In general, the rider wants a suspension spring to be soft in normal travel but if the rider hits bumps, it needs to be stiffer so the rider has a bottom out protection. In the prior art, another variation is to have one spring with two characteristics. Also, another variation is to have one spring inside the other where the softer spring is on the outside and the stiffer spring is on the inside. The problem with the prior art is that it's a static system. Once the rider selects the spring characteristics, the rider cannot adjust the spring compression characteristics or spring pre-load while riding.
The following 14 patents and published patent applications are the closest prior art references which are known to the inventors.
1. U.S. Pat. No. 3,559,976 issued to Joseph Jerz, Jr. on Feb. 2, 1971 for “Variable Stiffness Suspension System” (hereafter the “Jerz Patent”);
2. U.S. Pat. No. 4,727,820 issued to Kenzo Okazima on Oct. 5, 1976 for “Suspension For Two-Wheeled Vehicle” (hereafter the “Okazima Patent”);
3. U.S. Pat. No. 4,183,509 issued to Masao Nishikawa and assigned to Honda Giken Kogyo Kabushiki on Jan. 15, 1980 for “Shock Absorber for Vehicle Use” (hereafter the “Nishikawa Patent”);
4. U.S. Pat. No. Des. 262,959 issued to Arnold A. Cowan and assigned to Interpary Corporation on Feb. 9, 1982 for “Shock Absorber” (hereafter the “Cowan Design Patent”);
5. U.S. Design Pat. No. Des. 302,672 issued to Yutaka Ueno and assigned to Kabushiki Kaisha Showa Seisakusho on Aug. 8, 1989 for “Shock Absorber For Motorcycle” (hereafter the “Ueno Design Patent”);
6. U.S. Design Pat. No. Des. 368,054 issued to Steven J. Behrens and assigned to Answer Products, Inc. on Mar. 19, 1996 for “Bicycle suspension Fork” (hereafter the “Behrens Design Patent”);
7. U.S. Pat. No. 5,551,674 issued to Thore K. Johnsen on Sep. 3, 1996 for “Adjustable Resilient Support Device” (hereafter the “Johnsen Patent”);
8. U.S. Pat. No. 5,580,075 issued to Paul H. Turner et al. and assigned to Rockshox, Inc. on Dec. 3, 1996 for “Bicycle Fork Suspension With Exchangeable Spring Unit” (hereafter the '075 Turner Patent”);
9. U.S. Pat. No. 6,105,988 issued to Paul H. Turner et al. and assigned to RockShox, Inc. on Aug. 22, 2000 for “Adjustable Suspension System Having Positive And Negative Springs” (hereafter the '988 Turner Patent”);
10. U.S. Pat. No. 6,343,807 issued to James C. Rathbun and assigned to Answer Products, Inc. on Feb. 5, 2002 for “Multi-Travel Suspension Fork For Cycles” (hereafter the “Rathbun Patent”);
11. U.S. Pat. No. 6,471,197 issued to Peter Denk et al. and assigned to Denk Engineering GmbH on Oct. 29, 2002 for “Spring Device For Shock Absorber With Adjuster” (hereafter the “Denk Patent”);
12. U.S. Pat. No. 6,592,136 issued to William M. Becker and assigned to Fox Factory, Inc. on Jul. 15, 2003 for “Bicycle Fork Cartridge Assembly” (hereafter the “Becker Patent”);
13. London Patent Number 36704/72 issued to Kayaba Kogyo Kabushiki Kaisha on Aug. 7, 1972 for “Suspension For Two-Wheeled Vehicle” (hereafter the “Kaisha London Patent”);
14. International Publication Number WO 2005/054046 issued to Brian Jordan et al. and assigned to SRAM Corporation on Jun. 16, 2005 for “Adjustable Gas Spring Suspension System” (hereafter the “Jordan International Publication”).
With respect to the Jerz Patent, this deals with a vehicle suspension system where there is a combination of a hard spring and a soft spring, and the travel of the soft spring is set by various stops and limit stops at certain locations near the bottom and near the top of the spring. Specifically the concept is “a vehicle suspension system including two springs connected in series, with one of the springs being stiffer than the other, and with the springs being so related that under normal load conditions the softer of the two springs is effected to provide a very gently cushioned ride, while upon the imposition of heavier load forces, the vehicle is supported more stiffly and primarily by the stronger spring. The conversion between these two conditions may be effected automatically, by engagement under heavy load conditions of stop shoulders acting to limit compression of the light spring. Similarly, upon excessive extension of the springs, an additional set of stop shoulder may automatically become effective to limit the amount of extension of the softer spring and cause the stiffer spring to resist further extension. A shock absorber may be utilized in conjunction with the springs, and may itself carry or include one or more of the stop shoulders”.
The Okazima Patent deals with a vehicle suspension system for a fork assembly. Specifically the concept is to adjust the amount of spring force with a knob (36), where the appropriate selection of the position of the stopper (47) or of the cam seat (33) caused by rotating knob (36) to rotate the cam seat thereby changing the relative position of the legs (34) with respect to the cam surfaces (29) of the cap (27) and the second helical spring (45) may be preloaded or the preload of the second helical spring (45) may be appropriately varied.
The Nishikawa Patent discloses the ability to adjust the tension of the shock absorber by utilizing a dial (11) or dial (111) as shown in FIG. 6. The shock absorber itself is comprised of a piston cylinder assembly. A coiled suspension spring (16) is arranged between an annular upper spring seat (14) supported on the upper mounting member (11) and a lower spring seat (15) vertically adjustably mounted on the external periphery of the tubular casing (2) by appropriate well known means. The upper surface of the spring seat (14) is provided on the top surface with a scale (23) to indicate the intensity of the damping force. The upper spring seat (14) thus serves as a damping force adjusting dial rotatable relative to the upper mounting member (11).
The Cowan Patent is a design patent which protects the shape of the object.
The Ueno Design Patent that protects the shape or ornamental beauty of a shock absorber for a motorcycle but does not disclose how the device functions.
The Behrens Patent is a design patent for a bicycle fork.
The Johnsen Patent discloses a dual sping damping system having an inner spring and an outer spring where the adjustment is made to the outer spring by the rotatable ball valve lever (22).
The '075 Turner Patent for a “Bicycle Fork Suspension With Exchangeable Spring Unit” relates to various damping systems that can be included in the bicycle fork, including a hydraulic system and the concept of adjusting a preload to a knob.
The '998 Turner Patent deals with adjustable springs which can be air springs or gas springs as well as coil and elastomer springs. This patent deals discloses a compressor piston and other additions in order to improve suspension response.
The Rathburn Patent discloses a suspension fork including an operating device mounted externally to the telescoping fork leg that permits the rider to selectively shorten or lengthen the extent of relative travel between the inner and outer tubular sections of the fork.
The Denk Patent discloses the concept of having a single spring on top which can be adjusted for spring distance length by a rotatable knob. Specifically, the patent in relevant part reads as follows “the fixed shock absorber (10) which is, for example, configured as a cartridge in a bicycle fork or as an independent shock absorber, comprises a shock absorber cover (12) having a thread about its periphery into which spring (14) engages, whereby the shock absorber (10), respectively absorber cover (12), is movably fixed relative to spring (14). Shock absorber (10) is a preferably fixed at a position relative to an embracing member. The end (16) of the spring (14) is fixed in a rotocap (18). The rotocap (18) is mounted rotatably about axis (20). Upon rotating cap (18), spring (14) turns so that the thread pitch of spring (14) displaces axially relative to the thread. For example when shock absorber cover (12) including thread is displaced upwardly as a consequence of a rotation of rotocap (18) by the spring (14) about the distance (22), the effective spring length, which corresponds to the spacing between rotocap (18) and absorber head (12), decreases from the dimension (24) to the dimension (26).”
The Becker Patent discloses the concept of an adjustment mechanism on top a bicycle which is a preload adjuster assembly with a single spring on which the load is may be adjusted. The preload adjuster assembly (330) is desirably provided to allow adjustment of the preload on the second spring (322). The preload adjuster assembly (330) generally comprises an adjuster cap (332), an adjuster shaft (334) or barrel (336) and an adjuster knob (338). Rotation of the adjuster knob provides a plurality of preload adjustments.
The London Patent deals with adjustable hydraulic damper units that disclose the ability to adjust the effectiveness of spring damping via an adjustment knob.
The Jordan Patent discloses an Adjustable Gas Spring Suspension System”.
There is a significant need for an improved shock distribution system that may be adjusted while the vehicle is in operation. Further there is a need for suspension system that has soft and firm setting adjustable spring characteristics.